If you are using the subway pass strictly for travel for work and not commuting to or from your regular place of work then you would deduct it under travel expenses.
- Sign into your return
- Click Take me to my return
- Federal
- Income and Expenses
- Review or Edit next to Self-Employment income and expenses
- Review next to your business
- Scroll down click "Add expenses for this work"
- Click Business Travel
If this is for work as an employee or personal use, it is not deductible. If it is used for both self-employment and personal you would need to prorate the expense.